Friday isn't a parade taping day, but there are other spots around MK that they are taping in. They will let the 'extras' in at 7:30ish. They are shepherded to their respective spots. The park opened at it's normal time, 9 I believe on that day.
You really won't encounter any huge crowds based on the tapings. Those involved in the taping, as extras, are told to remain in their designated areas. This lasts for about 4 hrs or so. Other park goers shouldn't have a big problem getting around these areas. In fact, as the morning goes by, the 'extras' get tired and wander off, leaving spots open for those who didn't sign up!!! It's tiring standing in one spot, trying to look excited on demand for hours on end. My knees/back gave out after 3 hrs of it.